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accounts/abi: fixed unpacking in to already slice interfaces

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Previously it was assumed that wheneven type `[]interface{}` was given
that the interface was empty. The abigen rightfully assumed that
interface slices which already have pre-allocated variable sets to be
assigned.

This PR fixes that by checking that the given `[]interface{}` is larger
than zero and assigns each value using the generic `set` function (this
function has also been moved to abi/reflect.go) and checks whether the
assignment was possible.

The generic assignment function `set` now also deals with pointers
(useful for interface slice mentioned above) by dereferencing the
pointer until it finds a setable type.
This commit is contained in:
Jeffrey Wilcke 2016-05-11 13:21:25 +02:00
parent 5782164a35
commit 91a7a4a786
3 changed files with 94 additions and 31 deletions
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59
accounts/abi/abi.go
View File

@ -238,8 +238,16 @@ func (abi ABI) Unpack(v interface{}, name string, output []byte) error {
return fmt.Errorf("abi: unmarshalling empty output")
}
value := reflect.ValueOf(v).Elem()
typ := value.Type()
// make sure the passed value is a pointer
valueOf := reflect.ValueOf(v)
if reflect.Ptr != valueOf.Kind() {
return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
}
var (
value = valueOf.Elem()
typ = value.Type()
)
if len(method.Outputs) > 1 {
switch value.Kind() {
@ -268,6 +276,25 @@ func (abi ABI) Unpack(v interface{}, name string, output []byte) error {
return fmt.Errorf("abi: cannot marshal tuple in to slice %T (only []interface{} is supported)", v)
}
// if the slice already contains values, set those instead of the interface slice itself.
if value.Len() > 0 {
if len(method.Outputs) > value.Len() {
return fmt.Errorf("abi: cannot marshal in to slices of unequal size (require: %v, got: %v)", len(method.Outputs), value.Len())
}
for i := 0; i < len(method.Outputs); i++ {
marshalledValue, err := toGoType(i, method.Outputs[i], output)
if err != nil {
return err
}
reflectValue := reflect.ValueOf(marshalledValue)
if err := set(value.Index(i).Elem(), reflectValue, method.Outputs[i]); err != nil {
return err
}
}
return nil
}
// create a new slice and start appending the unmarshalled
// values to the new interface slice.
z := reflect.MakeSlice(typ, 0, len(method.Outputs))
@ -296,34 +323,6 @@ func (abi ABI) Unpack(v interface{}, name string, output []byte) error {
return nil
}
// set attempts to assign src to dst by either setting, copying or otherwise.
//
// set is a bit more lenient when it comes to assignment and doesn't force an as
// strict ruleset as bare `reflect` does.
func set(dst, src reflect.Value, output Argument) error {
dstType := dst.Type()
srcType := src.Type()
switch {
case dstType.AssignableTo(src.Type()):
dst.Set(src)
case dstType.Kind() == reflect.Array && srcType.Kind() == reflect.Slice:
if !dstType.Elem().AssignableTo(r_byte) {
return fmt.Errorf("abi: cannot unmarshal %v in to array of elem %v", src.Type(), dstType.Elem())
}
if dst.Len() < output.Type.SliceSize {
return fmt.Errorf("abi: cannot unmarshal src (len=%d) in to dst (len=%d)", output.Type.SliceSize, dst.Len())
}
reflect.Copy(dst, src)
case dstType.Kind() == reflect.Interface:
dst.Set(src)
default:
return fmt.Errorf("abi: cannot unmarshal %v in to %v", src.Type(), dst.Type())
}
return nil
}
func (abi *ABI) UnmarshalJSON(data []byte) error {
var fields []struct {
Type string

31
accounts/abi/abi_test.go
View File

@ -289,6 +289,37 @@ func TestSimpleMethodUnpack(t *testing.T) {
}
}
func TestUnpackSetInterfaceSlice(t *testing.T) {
var (
var1 = new(uint8)
var2 = new(uint8)
)
out := []interface{}{var1, var2}
abi, err := JSON(strings.NewReader(`[{"type":"function", "name":"ints", "outputs":[{"type":"uint8"}, {"type":"uint8"}]}]`))
if err != nil {
t.Fatal(err)
}
marshalledReturn := append(pad([]byte{1}, 32, true), pad([]byte{2}, 32, true)...)
err = abi.Unpack(&out, "ints", marshalledReturn)
if err != nil {
t.Fatal(err)
}
if *var1 != 1 {
t.Errorf("expected var1 to be 1, got", *var1)
}
if *var2 != 2 {
t.Errorf("expected var2 to be 2, got", *var2)
}
out = []interface{}{var1}
err = abi.Unpack(&out, "ints", marshalledReturn)
expErr := "abi: cannot marshal in to slices of unequal size (require: 2, got: 1)"
if err == nil || err.Error() != expErr {
t.Error("expected err:", expErr, "Got:", err)
}
}
func TestPack(t *testing.T) {
for i, test := range []struct {
typ string

35
accounts/abi/reflect.go
View File

@ -16,7 +16,10 @@
package abi
import "reflect"
import (
"fmt"
"reflect"
)
// indirect recursively dereferences the value until it either gets the value
// or finds a big.Int
@ -62,3 +65,33 @@ func mustArrayToByteSlice(value reflect.Value) reflect.Value {
reflect.Copy(slice, value)
return slice
}
// set attempts to assign src to dst by either setting, copying or otherwise.
//
// set is a bit more lenient when it comes to assignment and doesn't force an as
// strict ruleset as bare `reflect` does.
func set(dst, src reflect.Value, output Argument) error {
dstType := dst.Type()
srcType := src.Type()
switch {
case dstType.AssignableTo(src.Type()):
dst.Set(src)
case dstType.Kind() == reflect.Array && srcType.Kind() == reflect.Slice:
if !dstType.Elem().AssignableTo(r_byte) {
return fmt.Errorf("abi: cannot unmarshal %v in to array of elem %v", src.Type(), dstType.Elem())
}
if dst.Len() < output.Type.SliceSize {
return fmt.Errorf("abi: cannot unmarshal src (len=%d) in to dst (len=%d)", output.Type.SliceSize, dst.Len())
}
reflect.Copy(dst, src)
case dstType.Kind() == reflect.Interface:
dst.Set(src)
case dstType.Kind() == reflect.Ptr:
return set(dst.Elem(), src, output)
default:
return fmt.Errorf("abi: cannot unmarshal %v in to %v", src.Type(), dst.Type())
}
return nil
}